This invention relates generally to systems for manipulating video signals, and more particularly, to a digital system which manipulates digitized video information after it has been stored in a memory.
Conventional video special effects systems utilize analog circuitry for directly manipulating an analog video signal. In such systems, an input video signal is subjected to the effects of modifying analog signals such as ramp, sawtooth, and other signals, to produce a variety of special effects. Such effects may be chroma-keyed to produce picture effects resembling hearts, stars, circles, and other predetermined designs. The known analog systems, however, are difficult to maintain and operate, require complex and expensive analog circuitry which must be finely tuned before each use, and must generally be operated so as to be in synchrony with the video input signal. Moreover, such analog systems are generally quite limited in the number and nature of available special effects, and are not easily reprogrammed.
Digital systems are known which are specifically adapted to the generation of video special effects and which alleviate some of the problems of analog systems. Such known digital special effects systems, however, also operate directly upon the video data which is stored in memory in the form of pixels. As such, therefore, such digital video special effects systems generally require large amounts of data storage space and oftentimes must operate in synchrony with the video input signal. Accordingly, such systems are complex and expensive, thereby rendering them available only to large television studios. More importantly, this type of a video special effects system cannot produce rotative and other displacement effects.
A further known digital special effects arrangement utilizes computational circuitry which operates upon the data pertaining to the address locations of a memory which contains stored video information. This known address manipulating system is limited in its capabilities to compressing or expanding the video information, as it is presented on the video screen, and establishing video priority whereby selected portions of the video screen show only the video image having priority for that particular portion.
A further digital special effect system which utilizes the concept of restructuring memory addresses upon readout is adapted to produce mirror image effects and reversal effects. Moreover, this further known system enables conversion between video standards, illustratively between the NTSC North American System and the PAL European System.
It is a problem with the known systems which utilize address restructuring that a simple and economical technique for producing rotative and three dimensional effects has not been provided heretofore because complex equations which define the rotative effects must be solved quickly for each new pixel as it is placed on the video screen.
It is, therefore, an object of this invention to provide a digital special effects arrangement for video which can perform expansive, compressive, rotative, and other video image displacing effects. It is a further object of this invention to provide a special effects arrangement which performs video special effects by restructuring memory addresses during read out of the data stored in the memory in response to a predeterminable equation which defines the special effect.
It is a still further object of this invention to provide a special effect arrangement wherein the memory address of each pixel is restructured in accordance with a predeterminable equation which defines the desired special effect immediately prior to the placement of the pixel on the video screen.
It is yet another object of this invention to provide a video special effects processing system wherein memory address data is manipulated in accordance with predeterminable mathematical functions; the manipulations being performed in a hardware-implemented processor for solving a generalized equation.